<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>下拉列表</title>
</head>

<body>
    <form>
        <select name="guanji" id="">

           <!-- 1. select里至少包含一对option -->
           <!-- 2. 在option中定义select="select",当前项为默认选中项目。 -->

            
            <option value="zhongguo">中国</option>
            <option value="shanghai">上海</option>
            <option value="huoxing" selected="selected">火星</option>
            <option value="beijing">北京</option>
            <option value="hubei">湖北</option>
        </select>
    </form>
</body>

</html>